Talk Artificial nighttime lighting reduces the use of wildlife crossing structures by insectivorous bats in southeast Australia
  • Manisha Bhardwaj
    Bio statement : I am a PhD student at the Australian Research Centre for Urban Ecology (Royal Botanic Garden Victoria) and the University of Melbourne.  My PhD is investigating the impact of roads on insectivorous bats, in South-East Australia.  I am particularly interested in evaluating the impact of sensory pollution (i.e. light and noise pollution) on insectivorous bats.  Previously, I completed my B.Sc (Honours) at Queen’s University in Ontario, Canada where I investigated the impact of urbanization on personality and behaviour in Western Bluebirds.
    Country : AU
    Contact : mbhardwaj@student.unimelb.edu.au
    Website :
  • Kylie Soanes
    Bio statement : Dr. Kylie Soanes is a postdoctoral fellow at the Australian Research Centre for Urban Ecology, Royal Botanic Gardens Victoria, and an honorary research fellow at the University of Melbourne, Australia. Her research focuses on the conservation of wildlife within urban and human-dominated landscapes, using field and genetic approaches to address ecological questions and guide effective management. During her PhD research, Kylie evaluated the effectiveness of road-crossing structures for arboreal mammals, assessing the impacts on movement, survival and gene flow using a before-after-control-impact experiment.
    Country : AU
    Contact : ksoanes@unimelb.edu.au
    Website :
  • Jose Lahoz-Monfort
    Bio statement : Dr. José Lahoz-Monfort is a postdoctoral Research Fellow at the Quantitative and Applied Ecology Group at the University of Melbourne. He works at the interface between Statistics, Decision-making and Applied Ecology. His research focuses on wildlife monitoring techniques, demography and population dynamics, the study of species distributions, and the statistical methods that underpin these areas, while keeping in mind the ultimate step: how these feed into the decision-making process for biodiversity conservation and management, so that the allocation of the often scarce conservation resources can be optimized. He is also interested in the use of novel technologies to aid ecological research within a sound statistical framework for surveys design and data analysis.
    Country : AU
    Contact : jose.lahoz@unimelb.edu.au
    Website :
  • Lindy Lumsden
    Bio statement : Dr. Lindy Lumsden is a Principal Research Scientist with the Victorian Department of Environment, Land, Water and Planning, at the Arthur Rylah Institute for Environmental Research, in Melbourne, Australia. Lindy completed a Bachelor of Science, majoring in Zoology, at the University of Melbourne. She began her career in 1979 at the Museum of Victoria undertaking wildlife surveys, before moving to the Arthur Rylah Institute in 1982 where for the past 33 years she has undertaken applied ecological research on a wide range of mammals, specialising in insectivorous bats. She received her PhD from Deakin University in 2004, with her thesis on ‘The ecology and conservation of insectivorous bats in rural landscapes’. She has published widely in the Australian and international literature, and co-supervises post-graduate student to help inspire them in bat ecology. She was recently recognised for her contributions to bats by having the Northern Freetail Bat named in her honour for ‘her contribution to the study of Australian bat ecology, for her mentoring of students and for her advocacy for conservation of bats through public engagement’.
    Country : AU
    Contact : Lindy.Lumsden@delwp.vic.gov.au
    Website :
  • Rodney van der Ree
    Bio statement : Associate Professor Rodney van der Ree is the Deputy Director at The Australian Research Centre for Urban Ecology at The Royal Botanic Gardens Victoria and The University of Melbourne. Rodney is recognised internationally as an expert on the ecology of linear infrastructure and has presented the results of his research in plenary lectures and invited seminars across Australia and in Europe, USA, South Africa, and India. He consults widely with industry, government and NGOs, including with all levels of Government in Australia, the European Union and elsewhere. Rodney co-founded the Australasian Network for Ecology and Transportation (www.ecoltrans.net) and has just finished editing the 63-chapter “Handbook of Road Ecology”, with over 100 authors from 25 countries. Rodney has authored or co-authored over 60 refereed publications, 60 reports or popular articles, 100 conference presentations or public lectures and >30 media appearances.
    Country : AU
    Contact : rvdr@unimelb.edu.au
    Website :
Abstract

OBJECTIVES

Barrier-to-movement impacts of roads on wildlife may be amplified by the presence of artificial night-time lighting, such as street lights.  This may be particularly true for nocturnal wildlife such as insectivorous bats that often avoid large gaps in the canopy and areas of high light and noise, such as major highways.  Wildlife crossing underpasses (i.e. culverts and bridges) are often used to reduce road impacts.  Previously, we studied the use of these structures in southeast Australia by bats and determined that bats are more likely to use bridges than culverts.  In this study, we introduced light to these structures to evaluate if the presence of light alters the activity within and above the structures.

METHODS

We monitored the level of activity of bats (i.e. number of calls, recorded using Anabat bat detectors) under and above two types of crossing structures: wildlife underpass bridges, and wildlife culverts along a major freeway in southeast Australia.  We placed four detectors under the structure (two in the middle and one at each entrance, facing towards the middle of the structure), and four detectors on the road above the structure (two in the middle and one on each edge, facing towards the centre of the road).  Nightly bat activity was monitored at two bridges and two culverts simultaneously, with one structure of each pair designated control and the other impact.  At the impact sites, we lit the structure using LED light strips on 1m x 1.2m sheets of zinc powered by 12V batteries, and monitored activity for 16 days which were divided into three experimental phases: before (lights off for 4 nights), during (light on for 8 nights) and after (lights off for 4 nights).  Each structure was lit to an average of 10 lux (the standard light level for residential street lighting).  Control sites were monitored for the same 16 nights but without any lighting.  We used Poisson regression models, to estimate the change in activity between the phases of light presence and also compared the activity between structure types.

RESULTS

Bat activity was significantly lower when lights were introduced in crossing structures.  Furthermore, lit structures resulted in higher than usual activity above the structure at the road.  This suggests that bats actively avoided the lit passageway.

CONCLUSIONS

Light can have a significant impact on the behaviour and movement of insectivorous bats.  Our study showed that some bats will actively avoid lit areas, even if that means potentially accessing “unsafe” habitat such as a roadway.  These results suggest that bats will avoid roadways lit by streetlights, further amplifying barrier-to-movement impacts presented by roads.

CONTRIBUTIONS TO PRACTICE

Where possible, lighting should be avoided around critical bat habitat and crossing structures.  Road lighting significantly alters the behaviour of bats and may extend into the habitat surrounding the road. This will ultimately reduce the habitat quality and amount of suitable habitat available for bats to use while foraging, commuting, or reproducing.

Keywords
Light pollution; fauna passages; roads; insectivorous bats